Fixed showstopper in proposal.tasks.pull_updates
Fixed showstopper in proposal.tasks.pull_updates

Because Celery now uses JSON serialization instead of pickle, tasks
can't be called with model objects; they must be called with ids.

cityofsomerville/citydash,cityofsomerville/cornerwise,codeforboston/cornerwise,cityofsomerville/citydash,codeforboston/cornerwise,codeforboston/cornerwise,cityofsomerville/cornerwise,codeforboston/cornerwise,cityofsomerville/cornerwise,cityofsomerville/citydash,cityofsomerville/cornerwise,cityofsomerville/citydash